Usually, the one or more vertical guide rails of an elevator, which are used for guiding the elevator car inside an elevator shaft in a vertical direction, are supported by brackets, each of which is attached to a wall of the elevator shaft. However, the brackets may change their distance with respect to each other due to so called building contraction.
Building contraction is one event that affects most of civil constructions. It is caused by the settlement of the building and soil, mortar dehydration, etc., starting at the beginning of construction and continuing during some months until the building stabilizes. However, even after years a building may be affected by such contraction events (although comparable small with respect to the one at the beginning of the construction). The taller the building is, the bigger is the total length of contraction, reaching tens of centimeters in some cases, which also may affect the elevator and in particular its guide rail support structure.
In order to minimize these effects, clips used to fix the guide rail to the brackets may allow sliding between the guide rail and prevent the bracket and the guide rail from high stress or even structural failure such as buckling, irreversible deformation or the like. However, sliding clips with a low friction value may have a negative effect on the overall rigidity and ability of the guide rail support structure to support a high load. In contrast, fixed clips providing a high friction between the guide rail and the bracket, a high stiffness and a high ability of supporting loads may not be designed for compensating building contraction.
U.S. Pat. No. 1,925,867 shows an elevator guide rail supporting device with a spring clamp pressed against a bearing member for supporting the guide rail.